1. Field of the Invention
This invention relates generally to wireless and long distance carriers, Internet Service Providers (ISPs), and information content delivery services/providers and long distance carriers. More particularly, it relates to location services for the wireless industry.
2. Background of Related Art
It is desired to accurately locate the physical position of a wireless device (e.g., a wireless telephone) within a wireless network. There are currently two different types of architecture developed to accomplish a location based service (LSB): Control Plane location based services, and more recently User Plane location based services.
Older location based services utilize what is now called Control Plane location based services. A Control Plane location based service utilizes a management system to automate and build processes and perform inventory management. A User Plane location based service utilizes control or signaling messages to determine the location of a particular wireless device.
A key difference between these two technologies is that a Control Plane solution uses a control channel to communicate with the wireless device, while a User Plane solution uses the subscriber's traffic channel itself (e.g. IP bearer or SMS) to communicate with the wireless device. A Control Plane solution requires software updates to almost all the existing network components and wireless devices, while a User Plane solution is recognized as a more feasible solution for carriers to provide location-based services.
The concept known as User Plane location based service makes use of the user's bearer channel itself, e.g., IP bearer or SMS, to establish the communications required for initiating a positioning procedure. User Plane location based services have been introduced as an alternative location service architecture as defined in standard organizations, e.g., 3GPP.
Thus, User Plane location based services utilize contents of the communications itself to locate the wireless device. User Plane location based services focus on the TCP/IP capability of a wireless device such as a mobile telephone to generally bypass the carrier infrastructure and instead use, e.g., the Internet. There are significant advantages to the deployment of User Plane location based services, including an easier and more streamlined architecture than that of a Control Plane location based service. In this way, costly upgrades are avoided, and quick and relatively inexpensive deployment is possible using otherwise conventional system components.
In User Plane location based services, the inventors have noted that there is an issue related to location service procedure when the target mobile is roaming and IP bearer is used (IP bearer is the default bearer for User Plane location service solutions). Roaming refers to the physical movement of a wireless device among the territories covered by different wireless carriers.
In particular, based on conventional User Plane location service architecture, the target wireless device or mobile to be located must communicate with the Positioning Server (a.k.a. GMLC in 3GPP, MPC in 3GPP2) that is serving the cell where the wireless device camps. In this procedure, a PDP Context is established between the wireless device and the GGSN in the wireless device's Home Public Land Mobile Network (H-PLMN). The PDP Context is a communication channel established for the target wireless device to access IP networks, including an H-LCS Manager (a.k.a. H-GMLC in 3GPP, or H-MPC in 3GPP2), a Visited-LCS Manager (a.k.a. Visited-GMLC in 3GPP, or Visited MPC in 3GPP2), and/or a Positioning Server (a.k.a. SMLC in 3GPP, or PDE in 3GPP2).
However, the inventors herein realize that for security reasons, the IP networks of different PLMNs are separated with protective IP firewalls. Furthermore, inside a PLMN, the IP network is usually configured as a private network using private IP addresses. The IP connectivity to the Internet goes through a gateway router that provides NAT function. Yet, in currently defined User Plane location based services, a target wireless device must communicate with the positioning server in the Visited-PLMN via the GGSN in Home-PLMN, using the positioning server's private IP address provided by the Visited-LCS Manager. However, in a roaming scenario, it is realized that it is currently not permitted for a wireless device to communicate directly with a proper positioning server because of the various firewalls.
While User Plane location based solutions have been developed and deployed in a number of networks, support is not complete, especially when a GPRS IP bearer is used as the bearer. This invention introduces a methodology to resolve a key issue related to a roaming scenario for User Plane location based service solutions.
In conventional 3GPP network architectures, when a mobile initiates a packet data service session, called a PDP Context, the location SGNS will establish a connection to the GGSN indicated by an Access Point Name (APN) provided by the mobile. The GGSN identified by the APN usually resides in the Home Public Land Mobile Network (H-PLMN) of the mobile. So, in the roaming scenario, an IP bearer is established between the MS and the GGSN in the Home PLMN. Therefore, all the IP traffic to/from the mobile is tunneled to the Home PLMN.
With a Release 6 architecture of the 3GPP standard, a Gateway Mobile Location Center (GMLC) is able to communicate with other GMLCs that reside in different PLMNs, using an Lr interface. Thus, the Lr interface is allowed to go though the firewalls of PLMNs, attempting to provide adequate services in a roaming scenario.
In a typical Mobile Terminating (MT) location service in a roaming scenario, the mobile or wireless device must communicate with the local positioning server of a User Plane location based service (sometimes referred to as “SMLC” using 3GPP standards terminology), to exchange location information and request assistance and a positioning calculation depending upon the particular positioning method being used.
However, during the MT location service procedure of a conventional User Plane location based service, a wireless device will be provided with the IP address of the local positioning server. As the inventors have appreciated, usually this IP address is a private IP address. Thus, while in theory full roaming support seems to be enabled, the inventors herein have appreciated that in reality the wireless device is not always able to reach this IP host from a private network (H-PLMN) because it is protected by firewalls.
There is the need to provide roaming support for a real-world subscriber utilizing a User Plane location based service in an existing GPRS network architecture.